So here are a few pics of some of the 12 x 12 x 18 vivs I have set up, just to help you visualize. Even with just smaller vines, this size viv gets really filled up quickly (yeah, they need some pruning...).

I keep a 1.1 pair of imis in each of the first two, and the last one (with the Neo 'stairs' up the left wall) is for a pair of vanzos once I get them sexed. The two lower 'stairs' in that viv are the 'June Night' that I mentioned. The tips of each leaf get a little red spike on the end -- really cool.

Beautiful tanks SM! I have really struggled to get good looking tanks that size. I have two 12x12x18s and they never look proportionate or right. Thanks for the suggestions!